1. Field of the Invention
This invention relates to a mechanical knot which may be used to fasten a rope or cable to an object and which is capable of being quickly and easily detached even after the rope or cable has experienced considerable tension or strain.
2. Description of the Related Art
In many applications, including the field of sailing, it is desired to attach and detach a line, rope or cable to another object with a minimum of effort. One of the simplest and most commons means of attachment consists of tying a knot in the rope. While effective, a knot has the drawback of being very difficult to untie after the rope has been subject to tension. With today's synthetic materials such as KEVLAR or VECTRAN, such knots are for all practical purposes impossible to untie. A spiced joint is fine for attachment but does not allow detachment.
Another method of attaching a rope to an object uses an auxiliary fitting such as a shackle. The rope is either permanently or semi-permanently tied or spliced to the shackle. The shackle and not the rope is then used as the attachment or detachment point. U.S Pat. No. 5,769,475 issued to Tylaska on Jun. 23, 1998 discloses a snap shackle which provides an easy connection to secure a rope to an object. Such auxiliary fittings have the drawback of being both expensive and heavy. In some fields such as the field of sailing it is desired to utilize a connection with as little weight as possible so as to maximize performance. Also in the field of sailing it is desirable to minimize weight so as to prevent damage or danger from free-swinging ropes. The auxiliary fitting such as the metal snap shackle thus has many drawbacks.
Still another method of fastening a rope or cable to an object is the use of a mechanical knot. For instance, U.S Pat. Nos. 4,872,240 and 4,918,785 issued to Spinner et al on Oct. 10, 1989 and Apr. 24, 1990 respectively disclose tube-like devices for securing a rope and U.S. Pat. No. 5,577,299 issued to Thompson et al. on Nov. 26, 1996 discloses a semi-rigid spring-like device for also securing a rope.
A major drawback with prior art apparatus is those solutions are directed to attaching a single strand of rope in a knot configuration instead of attaching a spliced or tied loop in a hitch configuration. With the single strand configuration, there is the possibility of slippage of the end of the strand back through the knot, thus causing the knot to become untied. In addition, there is the awkwardness of the tail of left over rope sticking out of the mechanical knot. A mechanical knot which utilizes a double strand in a loop or hitch configuration does not have such drawbacks. U.S. Pat. No. 6,192,558 issued to Badura on Feb. 27, 2001 discloses a mechanical trucker's knot with locking clasp which utilizes a hitch type loop but pertains to a locking rope device mainly for tightening slack.
Another drawback with prior art mechanical knot inventions is their complicated and time consuming nature for attaching and detaching the rope. Especially in the field of sailing, one usually does not have the luxury of time or full dexterity from numb fingers to be able to operate such devices sufficiently.
Still another drawback from prior art mechanical knots is the sharp radius through which the rope must be bent. Rope becomes significantly weaker when bent around tight corners and it is not unreasonable for it to loose over 50% of its strength.
A device made by Tseil Tonshoff in Germany is used for a tow rope that suitable for creating a loop that can be placed around the object that is to be towed. Typically, this is an automobile. The design of this device does not allow it to be removed from the line as the opening through the plastic body is sufficient only for a single line. Further, a double lock is not provided.
U.S. Pat. No. 525,770, issued on Sep. 11, 1894, to Edward F. Parker, discloses a rope hitching device, having a concave plate from which two spiral sleeves extend in opposite directions for attaching two ends of a rope together for securing a rope to a hitching post.
U.S. Pat. No. 749,847, issued on Jan. 19, 1904, to Wallace B. Curtis, discloses a bale-tie device consisting of a metal plate having a double line of locking slots and notches for connecting two ends of a bailing line.
U.S. Pat. No. 1,452,338, issued on Apr. 17, 1923, to William J. Flowers, discloses a rope and cable tie comprising of a U-shaped channel cross member with slots into which part of the rope is inserted and fed back through so as to form a slip-proof loop.
U.S. Pat. No. 1,613,635, issued on Jan. 11, 1927, to John O. E. Zimmerlund, discloses a rope fastening device comprising of a plate which two holes whereas one hole is enlarged.
U.S. Pat. No. 1,718,641, issued on Jun. 25, 1929, to Henry E. Forman, disclosed a rope fastener consisting of a slotted U-shaped channel which side bars into which a rope can be knotted around.
U.S. Pat. No. 2,595,806, issued on May 6, 1952, to Edward L. Morris, discloses a rope fitting comprising of a grooved cylinder which a hook on its end. The rope can be seated into the grooves and tied so as to prevent slippage.
U.S. Pat. No. 3,094,755, issued on Jun. 25, 1963, to Jean C. Casanave, discloses a rope and connector assembly particularly useful for securing boats and consists of two parallel tubular passages through which a rope can be passed to form a slip-proof loop.
U.S. Pat. No. 4,872,240 issued on Oct. 10, 1989, to Ralphael F. Spinner et al., discloses a steel knot-type device comprising of two metal rings held together by a multitude of connectors consisting of a length of pipe or tube with one or more elongated slotted portions in its walls.
U.S. Pat. No. 4,918,785 issued on Apr. 24, 1990, to Ralphael F. Spinner et al., discloses a length of pipe or tube with one or more elongated slotted portions in its walls.
U.S. Pat. No. 5,577,299 issued on Nov. 26, 1996, to Carl. W. Thompson et al., discloses a quick-release mechanical knot device consisting of a semi-rigid elongated stock member having at least two circular orifices formed at opposite ends of a curvilinear intermediate portion.
U.S. Pat. No, 5,766,700, issued on Jun. 16, 1998, to Cedric M. Borcherds, discloses a loop fastening device comprising of a hollow conical body with an opening at its base and a slotted aperture at its apex.
U.S. Pat. No. 6,192,558, issued on Feb. 27, 2001, to Michael W. Badura discloses a mechanical trucker's knot with locking clasp which utilizes a hitch type loop but pertains to a locking rope device mainly for tightening slack.
U.S. Pat. No. 6,460,226, issued on Oct. 8, 2002 to Dennis Ray Smith et al., discloses a method and device for securing a knot comprising a tubular member around which a pre-stretched elastomeric band which is disposed in a manner similar to placing “shrink wrap” tubing around the knot.